Network Working Group J. Postel
Request for Comments: 820 J. Vernon
January 1983
Obsoletes RFCs: 790, 776, 770, 762,
758, 755, 750, 739, 604, 503, 433, 349
Obsoletes IENs: 127, 117, 93
ASSIGNED NUMBERS
This Network Working Group Request for Comments documents the currently
assigned values from several series of numbers used in network protocol
implementations. This RFC will be updated periodically, and in any case
current information can be obtained from Jon Postel. The assignment of
numbers is also handled by Jon, subject to the agreement between
DARPA/IPTO and DDN/PMO about number allocation, documented in Appendix A
of this RFC. If you are developing a protocol or application that will
require the use of a link, socket, port, protocol, or network number
please contact Jon to receive a number assignment.
Jon Postel
USC - Information Sciences Institute
4676 Admiralty Way
Marina del Rey, California 90291
phone: (213) 822-1511
ARPANET mail: POSTEL@ISIF
The ARPANET community is making the transition form the ARPANET to the
ARPA Internet. This has been characterized as the NCP/TCP transition
[63], although many other the protocols are involved, too. The working
documents for the new Internet environment have been collected by the
Network Information Center (NIC) in a book entitled the "Internet
Protocol Transition Workbook" [62].
Most of the protocols mentioned here are documented in the RFC series of
notes. The more prominent and more generally used are documented in the
"Internet Protocol Transition Workbook" or in the old "Protocol
Handbook" [17] prepared by the NIC. Some of the items listed are
undocumented.
In all cases the name and mailbox of the responsible individual is
indicated. In the lists that follow, a bracketed entry, e.g., [17,iii],
at the right hand margin of the page indicates a reference for the
listed protocol, where the number cites the document and the "iii" cites
the person.
Postel [Page 1]

RFC 820 January 1983
Assigned Numbers
APPENDIX A
APPENDIX A
----------
This appendix summarizes the agreements reached by the DDN/PMO and
DARPA at a September 1982 meeting concerning the allocation and
assignment of the various numbers associated with DoD Protocol
Standards and the DARPA Experimental Standards.
Recommended policy is summarized for each type of number assignment
of concern:
Network Identifiers used by the Internet Protocol
It is recommended that the available number spaces for class A,
B, and C network addresses be allocated among R&D, DoD and
commercial uses, and that assignments of these addresses be the
responsibility respectively of DARPA, DCA PCCO/DDN and the
National Bureau of Standards. The recommended allocations are
given below.
Class A
R&D allocation: 8 nets assigned by: ARPA
DoD allocation: 24 nets assigned by: TBD
Commercial allocation: 94 nets assigned by: TBD
Reserved Addresses: 0,127
Class B
R&D allocation: 1024 nets assigned by: ARPA
DoD allocation: 3072 nets assigned by: TBD
Commercial allocation: 12286 nets assigned by: TBD
Reserved Addresses: 0,16383
Class C
R&D allocation: 65536 nets assigned by: ARPA
DoD allocation: 458725 nets assigned by: TBD
Commercial allocation: 1572862 nets assigned by: TBD
Reserved Addresses: 0,2097151
Class D
All addresses in this class are reserved for future use,
possibly in support of multicast services. They should be
allocated to R&D use for the present.
Postel [Page 20]

RFC 820 January 1983
Assigned Numbers
APPENDIX A
Within the R&D community, it will be the policy that network
identifiers will only be granted to applicants who show
evidence that they are acquiring standard Bolt Beranek and
Newman gateway software or have implemented or are acquiring a
gateway meeting the External Gateway Protocol requirements.
Acquisition of the Berkeley BSD 4.2 UNIX software might be
considered evidence of the latter.
Experimental networks which later become operational need not
be renumbered if that would cause hardships. Rather, the
identifiers could be moved from R&D to DoD or Commercial
status. Thus, network identifiers may change state among R&D,
DoD and commercial, but the number of identifiers allocated to
each use should remain constant. To make possible this fluid
assignment, it is recommended that the network identifier
spaces not be allocated by simple partition but rather by
specific assignment. It is recommended that DDN/PMO or its
designee keep track of the assignments made by DARPA, DDN and
NBS to ensure that allocation remains as suggested.
Protocol Identifiers
In general, all assignments will be made by the R&D community,
but any numbers which become R&D, DoD, national or
international standards will be marked as such in this RFC.
Protocol identifiers 0 and 255 are reserved.
95 protocol identifiers are allocated for assignment to DoD
standards, 32 for R&D use, and 127 for Commercial, national or
international standards.
Port Numbers
A recommendation for allocation and assignment of port numbers
is to be developed jointly by representatives of the ICCB and
PSTP.
ARPANET Link Numbers
All unnecessary link number usage will be eliminated by joint
effort of the ICCB, PSTP and BBN. BBN will give consideration
to the use of link numbers to promote interoperability among
various ARPANET interfaces and report to the ICCB, PSTP and
DDN/PMO. Examples of possible interoperability issues are:
Postel [Page 21]

RFC 820 January 1983
Assigned Numbers
APPENDIX A
(i) interoperability of 1822 and X.25 interfaces
(ii) interoperability of SIP and other interfaces
(iii) logical addressing or other special services
IP Version Numbers
These numbers will be assigned only by the R&D community for
the purpose of exploring alternatives in internet protocol
service expansion, such as inclusion of stream protocol (ST)
services.
TCP, IP and Telnet Option Identifiers
These numbers will be assigned by the R&D community. Any
permanent or experimental assignments will be identified in the
documents specifying those protcols.
Implementation:
This policy recommendation has not been fully implemented as yet.
Currently Jon Postel is acting coordinator for all number
assignments.
Postel [Page 22]